The present disclosure relates to a multilayer ceramic capacitor and a board having the same mounted thereon.
Multilayer ceramic capacitors, multilayer chip electronic component, are chip type condensers mounted on printed circuit boards of several electronic products such as image devices, for example, liquid crystal displays (LCD), plasma display panels (PDP), and the like, computers, smart phones, cellular phones, and the like, to serve to charge or discharge electricity.
The multilayer ceramic capacitors (MLCC) may be used as components of various electronic devices due to advantages such as a small size, high capacitance, and an easy mounting feature.
The multilayer ceramic capacitors may have a structure in which a plurality of dielectric layers and internal electrodes disposed between the dielectric layers and having different polarities are alternately stacked.
Particularly, power supplies for central processing units (CPU) of computers, or the like, cause voltage noise due to a rapid change in a load current in a process in which it provides a relatively low voltage.
Therefore, multilayer capacitors have been widely used as decoupling capacitors for suppressing voltage noise in power supplies.
It has been demanded for the multilayer ceramic capacitors for decoupling to have a lower equivalent series inductance (ESL) as an operation frequency is increased. Research into a technology for decreasing ESL has been actively undertaken.
Further, in order to more stably supply power, controllable ESR characteristics are demanded in the multilayer ceramic capacitors for decoupling.
In the case in which an ESR value of the multilayer ceramic capacitors is lower than a demanded level, an impedance peak at a parallel resonance frequency generated due to ESL of multilayer ceramic capacitors and plane capacitance of microprocessor packages may be increased, and impedance at a series resonance frequency of multilayer ceramic capacitors may be excessively decreased.
Therefore, ESR characteristics of multilayer ceramic capacitors for decoupling are required to be easily controlled so that users may implement flat impedance characteristics of a power distribution network.
In relation to the control of ESR, a method in which external and internal electrodes are formed of materials having relatively high electrical resistance may be considered. The above-mentioned method may provide relatively high ESR characteristics while maintaining a relatively low ESL structure according to the related art.
However, in the case in which a high resistance material is used as a material of external electrodes, a localized heat spot caused by a current concentration phenomenon due to a pin hole may be generated. Further, in the case in which a relatively high resistance material is used as a material of internal electrodes, the material of the internal electrodes should be continuously changed to be matched to a ceramic material depending on an increase in capacitance.
Therefore, since the method of controlling ESR according to the related art has the problem as described above, research into multilayer ceramic capacitors of which ESR may be controlled remains required.
In addition, in accordance with recent rapid development of mobile terminals such as tablet personal computers (PC), ultrabooks, or the like, microprocessors have also been changed into small high-integrated products.
As a result, the area of printed circuit boards has been decreased and a space in which decoupling capacitors are to be mounted has been limited. Therefore, multilayer ceramic capacitors satisfying these requirements have been continuously demanded.